首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   257篇
  免费   8篇
  国内免费   3篇
化学   167篇
晶体学   1篇
力学   7篇
数学   31篇
物理学   62篇
  2024年   1篇
  2023年   7篇
  2022年   15篇
  2021年   20篇
  2020年   15篇
  2019年   14篇
  2018年   12篇
  2017年   8篇
  2016年   11篇
  2015年   12篇
  2014年   18篇
  2013年   8篇
  2012年   14篇
  2011年   15篇
  2010年   15篇
  2009年   13篇
  2008年   6篇
  2007年   6篇
  2006年   12篇
  2005年   9篇
  2004年   4篇
  2003年   5篇
  2002年   5篇
  2001年   2篇
  2000年   2篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1989年   1篇
  1984年   2篇
  1983年   2篇
  1979年   1篇
  1978年   2篇
  1976年   1篇
排序方式: 共有268条查询结果,搜索用时 359 毫秒
61.
62.
63.
Journal of Thermal Analysis and Calorimetry - In the present work, a series of experiments were designed and conducted to prepare biodiesel from cottonseed oil and to blend it with octanol. The...  相似文献   
64.
Journal of Thermal Analysis and Calorimetry - In the original publication of the article, the affiliations of the third, fourth and fifth authors were incorrectly published.  相似文献   
65.
Tweezer-like molecular systems containing a redox-active tetrathiafulvalene vinylogue (TTFV) unit and two phenylboronate or phenylboronic acid endgroups were synthesized via the Cu-catalyzed alkyne azide coupling (i.e., click) reaction. The TTFV-phenylboronic acid derivative was found to show different differential pulse voltammetric (DPV) responses to various monosaccharides in aqueous DMSO at pH 7.41, suggesting potential use in electrochemical sensing of saccharides. Moreover, the TTFV-phenylboronate derivative exhibited strong binding to the fluoride ion, giving rise to sensitive electrochemical detection of the fluoride ion.  相似文献   
66.
Journal of Solid State Electrochemistry - Structural, electrical, and optical properties of SnS nanoparticles and films deposited by ultrasound-assisted chemical bath were studied. The SnS was...  相似文献   
67.
With association of acylpyrazolones and benzhydrazide, two novel Ligands BZ-PCBMCPMP ((Z)-N'-((4-chlorophenyl) (1-(3-chlorophenyl) 3-methyl-5-oxo-1,5-dihydro-4H-pyrazol-4-ylidene) methyl) benzohydrazide) and BZ-PCBPMP ((Z)-N'-((4-chlorophenyl) (1-phenyl) 3-methyl-5-oxo-1,5-dihydro-4H-pyrazol-4-ylidene) methyl) benzohydrazide)) with different O–N–O fashion were synthesized via Schiff base reaction, which on complexation with Zn(II) acetate dihydrate yields novel [Zn(BZ-PCBMCPMP)2] and [Zn-(BZ-PCBPMP)2] complexes with distorted octahedron framework. Structure elucidation was performed through several spectroscopic techniques such as FTIR, 1H-NMR, 13C NMR, TG-DTA, UV/Vis, and Single-crystal XRD. The non-electrolytic nature was confirmed through molar-conductance values. Single crystal X-ray study of the BZ-PCBPMP ligand shows intramolecular as well as intermolecular hydrogen bonding, giving rise to a H-bonded dimer. In [Zn-(BZ-PCBPMP)2] one ligand is symmetrically coordinating while the other is asymmetrically coordinating to the Zinc atom. Antimalarial property of ligands and complexes was also discovered by its efficient MIC activity against Chloroquine sensitive P. falciparum.  相似文献   
68.
Active nanocomposites synthesized by the electrochemical approach play a vital role in energy generation, conversion, and storage technologies. Recently, scientists began to explore the use of earth-rich transition metal-based materials to replace precious metal-based catalysts. Transition metals (TMs) based nickel (Ni) and their pnictides compounds such as phosphides and selenides exhibit good activity for hydrogen evaluation reaction (HER) and the entire water electrolysis process. In this study, we first prepared Ni(OH)2 and grown its layer on Ni foam (NF) and treated it with selenide (Se) and phosphide (P) then nickel-based selenide-phosphide catalyst (Ni–P–Se) was prepared by simultaneous selenization and phosphidation process for the first time. The as-obtained composite was then analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), elemental mapping and transmission electron microscope (TEM) means to study the composition, structure, and micro-morphology of materials. Furthermore, we also observed electrocatalytic water splitting activity using electrochemical cell. The results of electrochemical tests depicted that the selenization and phosphidation treatments significantly enhanced the electrocatalytic HER activity of the starting materials. The overpotentials required for Ni–P–Se to reach 10 ?mA ?cm?2 and 100 ?mA ?cm?2 were only 242 ?mV and 282 ?mV. The Tafel slope of Ni–P–Se is 151 ?mV dec?1, which is lower than that of nickel phosphide, selenide, and hydroxide indicating that selenide-phosphide enhances the HER reaction kinetics of the material, which in turn increases hydrogen output rate as compared with previous studies.  相似文献   
69.
In this study, we analyze the magnetohydrodynamic flow of magnetite-engine oil nanofluid in the presence of nonidentical shaped nanoparticles subject to the porous medium and velocity slip effect. Energy analysis is carried out with the Ohmic heating and thermal radiation impacts. The system of partial differential equations are transformed into the system of ordinary differential equations using similarity variable. The Hamilton–Crosser model is used. The exact solutions for the momentum and heat transport analysis are found. The impact of various emerging parameters on the velocity and temperature profiles are analyzed by graphs. Furthermore, the local skin friction and heat transfer rate are examined graphically. It is examined that the velocity field increases with an increment in the magnitude of ϕ and L. An increase in the value of Hartman number enhancing the temperature profile.  相似文献   
70.
Nonclassical multiphoton have attracted extensive attention to serve as entangled resources for quantum information technology. Here, the continuous-mode hyper-entangled W-class triphotons are theoretically generated through spontaneous six-wave mixing (SSWM) in 85Rb. In nonlinear optical response, Zeeman sub-states are high-dimensionally quantized by polarized dressing. High-dimensional entanglement is structured via atomic non-Hermitian nature. Through linear optical response, the temporal correlations are shaped via diverse polarized dressing. SSWM-based triphoton is a genuine triphoton possessing non-Gaussian tripartite entanglement. The high production rate is due to co-action of three strong input fields, electromagnetically induced transparency (EIT) protection, and slow light effect. Non-Hermitian nature endows the system with sensitive adjustability around exceptional points (EP). Eventually, the results demonstrate multiple SSWMs causing oscillations with multiple periods in three-photon temporal correlations for the nonlinear region, build a high-dimensional three-body entangled quantum network and transform multifarious profiles of the three-photon temporal correlations for the linear region. Especially, both high-dimensional and hyper entanglements are obtained, contributing to high quantum information capacity. Further, the system is switched among multiple states when non-Hermitian nature is manipulated by polarized dressing. The research opens a broad prospect for generating the hyper-entangled multiphoton with potential application in adjustable quantum networks of high information capacity.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号